Expedition to Panarea: study of the effects of acidification on marine benthic organisms

In the framework of the European ECO2 project Dr. Katja Guilini of the Marine Biology Research Group participated in an expedition to Panarea, one of the Aeolian Islands in the Mediterranen Sea (June 2-14th, 2013), together with colleagues from the Max Planck Institute for Microbiology (Bremen, Germany) and from GEOMAR (Kiel, Germany). 

Volcanic activity causes CO₂ gas-escape from the seafloor at scattered places around the island. The high CO₂ concentrations increase the acidity of the porewater in the seafloor and as such creates a ‘natural laboratory’ to study the effects of acidification on marine benthic organisms. Since CO₂ release is ongoing for several decennia to ages this is a prime location to investigate long-term effects of acidification. This research issue is relevant in both the framework of increasing CO₂ concentrations in the atmosphere and subsequently higher acidity of the oceans worldwide, and in the framework of the ECO2 project that assesses the possibility and risks of CO₂ storage in deeper layers of the seabed as temporarily solution for the alarming increase of CO₂ in the atmosphere.

The first focused sampling took place in June 2012. Natural sediments and seagrasses of locations where CO2 escapes as gas bubbles and background (reference) locations were sampled by divers from the HYDRA team (Elba, Italy). The aims were to study the fauna, environmental variables such as granulometry, chloroplast pigment concentrations, total organic carbon, acidity, oxygen concentration etc., and to perform experiments in situ. During the campaign in 2013, the same locations were visited to finish the in situ experiments that were implanted the year before to study the short- and mid-term effect of exposure of fauna to high CO2 concentrations on the one hand and the possibility to re-establish the communities after being exposed. Apart from that environmental variables were measured again to determine the stability of the ‘natural laboratory’ and Dr. Guilini performed experiments in the lab to measure respiration of meiobenthos under acidified and non-acidified conditions.